Stock Option Activity (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Options
Outstanding at beginning of period	1,816,690
Granted	1,308,138
Forfeited	(57,276)
Outstanding at end of period	3,067,552	1,816,690
Exercisable at March 31, 2021	1,061,401
Weighted-Average Exercise Price
Outstanding at beginning of period	$ 11.04
Granted	9.02
Forfeited	8.73
Outstanding at end of period	10.22	$ 11.04
Exercisable at March 31, 2021	$ 13.79
Weighted-Average Remaining Contractual Term
Outstanding at March 31, 2021	8 years 1 month 28 days	7 years 6 months 10 days
Exercisable at March 31, 2021	5 years 8 months 1 day
Aggregate Intrinsic Value
Outstanding at end of year	$ 1,634,000	$ 170,000
Exercisable at end of year	$ 566,000